From 44ccc2465c6af5bd811d8258bf744aaafd5392fc Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Wed, 3 Apr 2024 16:39:19 -0300 Subject: [PATCH] math: x86 trunc traps when FE_INEXACT is enabled (BZ 31603) The implementations of trunc functions using x87 floating point (i386 and x86_64 long double only) traps when FE_INEXACT is enabled. Although this is a GNU extension outside the scope of the C standard, other architectures that also support traps do not show this behavior. The fix moves the implementation to a common one that holds any exceptions with a 'fnclex' (libc_feholdexcept_setround_387). Checked on x86_64-linux-gnu and i686-linux-gnu. Reviewed-by: H.J. Lu --- math/Makefile | 2 + math/test-trunc-except-2.c | 67 +++++++++++++++++++ sysdeps/i386/fpu/{s_trunc.S => s_trunc.c} | 24 ++----- sysdeps/i386/fpu/{s_truncf.S => s_truncf.c} | 24 ++----- sysdeps/i386/fpu/s_truncl.S | 40 ----------- .../fpu/s_truncl.S => x86/fpu/s_truncl.c} | 23 ++----- 6 files changed, 87 insertions(+), 93 deletions(-) create mode 100644 math/test-trunc-except-2.c rename sysdeps/i386/fpu/{s_trunc.S => s_trunc.c} (69%) rename sysdeps/i386/fpu/{s_truncf.S => s_truncf.c} (68%) delete mode 100644 sysdeps/i386/fpu/s_truncl.S rename sysdeps/{x86_64/fpu/s_truncl.S => x86/fpu/s_truncl.c} (70%) diff --git a/math/Makefile b/math/Makefile index 121fe2881a..a9fef9e2db 100644 --- a/math/Makefile +++ b/math/Makefile @@ -539,6 +539,7 @@ tests = \ test-tgmath-int \ test-tgmath-ret \ test-tgmath2 \ + test-trunc-except-2 \ tst-CMPLX \ tst-CMPLX2 \ tst-definitions \ @@ -993,6 +994,7 @@ CFLAGS-test-nan-const.c += -fno-builtin CFLAGS-test-ceil-except-2.c += -fno-builtin CFLAGS-test-floor-except-2.c += -fno-builtin +CFLAGS-test-trunc-except-2.c += -fno-builtin include ../Rules diff --git a/math/test-trunc-except-2.c b/math/test-trunc-except-2.c new file mode 100644 index 0000000000..8933c6ab41 --- /dev/null +++ b/math/test-trunc-except-2.c @@ -0,0 +1,67 @@ +/* Test trunc functions do not disable exception traps. + Copyright (C) 2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include + +#ifndef FE_INEXACT +# define FE_INEXACT 0 +#endif + +#define TEST_FUNC(NAME, FLOAT, SUFFIX) \ +static int \ +NAME (void) \ +{ \ + int result = 0; \ + volatile FLOAT a, b __attribute__ ((unused)); \ + a = 1.5; \ + /* trunc must work when traps on "inexact" are enabled. */ \ + b = trunc ## SUFFIX (a); \ + /* And it must have left those traps enabled. */ \ + if (fegetexcept () == FE_INEXACT) \ + puts ("PASS: " #FLOAT); \ + else \ + { \ + puts ("FAIL: " #FLOAT); \ + result = 1; \ + } \ + return result; \ +} + +TEST_FUNC (float_test, float, f) +TEST_FUNC (double_test, double, ) +TEST_FUNC (ldouble_test, long double, l) + +static int +do_test (void) +{ + if (feenableexcept (FE_INEXACT) == -1) + { + puts ("enabling FE_INEXACT traps failed, cannot test"); + return 77; + } + int result = float_test (); + feenableexcept (FE_INEXACT); + result |= double_test (); + feenableexcept (FE_INEXACT); + result |= ldouble_test (); + return result; +} + +#include diff --git a/sysdeps/i386/fpu/s_trunc.S b/sysdeps/i386/fpu/s_trunc.c similarity index 69% rename from sysdeps/i386/fpu/s_trunc.S rename to sysdeps/i386/fpu/s_trunc.c index 40e45c9f9c..ac16f4967c 100644 --- a/sysdeps/i386/fpu/s_trunc.S +++ b/sysdeps/i386/fpu/s_trunc.c @@ -1,5 +1,5 @@ -/* Truncate double value. - Copyright (C) 1997-2024 Free Software Foundation, Inc. +/* Round to integer, toward zero. i386 version. + Copyright (C) 2024 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -16,22 +16,10 @@ License along with the GNU C Library; if not, see . */ -#include #include -ENTRY(__trunc) - fldl 4(%esp) - subl $32, %esp - cfi_adjust_cfa_offset (32) - fnstenv 4(%esp) - movl $0xc00, %edx - orl 4(%esp), %edx - movl %edx, (%esp) - fldcw (%esp) - frndint - fldenv 4(%esp) - addl $32, %esp - cfi_adjust_cfa_offset (-32) - ret -END(__trunc) +#define FUNC __trunc +#define TYPE double +#define FE_OPTION FE_TOWARDZERO +#include "s_nearestint_387_template.c" libm_alias_double (__trunc, trunc) diff --git a/sysdeps/i386/fpu/s_truncf.S b/sysdeps/i386/fpu/s_truncf.c similarity index 68% rename from sysdeps/i386/fpu/s_truncf.S rename to sysdeps/i386/fpu/s_truncf.c index 0b26e09d61..240d3507ef 100644 --- a/sysdeps/i386/fpu/s_truncf.S +++ b/sysdeps/i386/fpu/s_truncf.c @@ -1,5 +1,5 @@ -/* Truncate float value. - Copyright (C) 1997-2024 Free Software Foundation, Inc. +/* Round to integer, toward zero. i386 version. + Copyright (C) 2024 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -16,22 +16,10 @@ License along with the GNU C Library; if not, see . */ -#include #include -ENTRY(__truncf) - flds 4(%esp) - subl $32, %esp - cfi_adjust_cfa_offset (32) - fnstenv 4(%esp) - movl $0xc00, %edx - orl 4(%esp), %edx - movl %edx, (%esp) - fldcw (%esp) - frndint - fldenv 4(%esp) - addl $32, %esp - cfi_adjust_cfa_offset (-32) - ret -END(__truncf) +#define FUNC __truncf +#define TYPE float +#define FE_OPTION FE_TOWARDZERO +#include "s_nearestint_387_template.c" libm_alias_float (__trunc, trunc) diff --git a/sysdeps/i386/fpu/s_truncl.S b/sysdeps/i386/fpu/s_truncl.S deleted file mode 100644 index dfd0ca4a57..0000000000 --- a/sysdeps/i386/fpu/s_truncl.S +++ /dev/null @@ -1,40 +0,0 @@ -/* Truncate long double value. - Copyright (C) 1997-2024 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - . */ - -#include -#include - -ENTRY(__truncl) - fldt 4(%esp) - subl $32, %esp - cfi_adjust_cfa_offset (32) - fnstenv 4(%esp) - movl $0xc00, %edx - orl 4(%esp), %edx - movl %edx, (%esp) - fldcw (%esp) - frndint - fnstsw - andl $0x1, %eax - orl %eax, 8(%esp) - fldenv 4(%esp) - addl $32, %esp - cfi_adjust_cfa_offset (-32) - ret -END(__truncl) -libm_alias_ldouble (__trunc, trunc) diff --git a/sysdeps/x86_64/fpu/s_truncl.S b/sysdeps/x86/fpu/s_truncl.c similarity index 70% rename from sysdeps/x86_64/fpu/s_truncl.S rename to sysdeps/x86/fpu/s_truncl.c index e3d64a84e8..e2bac7fa38 100644 --- a/sysdeps/x86_64/fpu/s_truncl.S +++ b/sysdeps/x86/fpu/s_truncl.c @@ -1,5 +1,5 @@ -/* Truncate long double value. - Copyright (C) 1997-2024 Free Software Foundation, Inc. +/* Round to integer, toward zero. x86 version. + Copyright (C) 2024 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -17,20 +17,9 @@ . */ #include -#include -ENTRY(__truncl) - fldt 8(%rsp) - fnstenv -28(%rsp) - movl $0xc00, %edx - orl -28(%rsp), %edx - movl %edx, -32(%rsp) - fldcw -32(%rsp) - frndint - fnstsw - andl $0x1, %eax - orl %eax, -24(%rsp) - fldenv -28(%rsp) - ret -END(__truncl) +#define FUNC __truncl +#define TYPE long double +#define FE_OPTION FE_TOWARDZERO +#include "s_nearestint_387_template.c" libm_alias_ldouble (__trunc, trunc)